#include <stdio.h>
#include <stdlib.h>
#include <string.h>

main(int argc, char *argv[])
{
	int i, j;
	char buf[5000];
	FILE *fp;
	char **lp = (char **) malloc(100 * sizeof(char *));
	int nbuf = 100;

	if (argc == 1)
		fp = stdin;
	else
		fp = fopen(argv[1], "r");
	for (i = 0; fgets(buf, sizeof buf, fp) != NULL; i++) {
		if (i >= nbuf) {
			nbuf *= 2;
			lp = (char **) realloc(lp, nbuf * (sizeof(char *)));
		}
		lp[i] = strdup(buf);
	}
	for (j = i-1; j >= 0; j--)
		printf("%s", lp[j]);
}